/Engine/Source/Runtime/CoreUObject/Public/UObject/PackageTrailer.h
Adds a payload to the builder to be written to the trailer. Duplicate payloads will be discarded and only a single instance stored in the trailer.
void AddPayload ( const [FIoHash](API\Runtime\Core\IO\FIoHash) & Identifier, [FCompressedBuffer](API\Runtime\Core\Compression\FCompressedBuffer) Payload, [UE::Virtualization::EPayloadFilterReason](API\Runtime\Core\Virtualization\UE__Virtualization__EPayloadFilt-) Filter, [AdditionalDataCallback](API\Runtime\CoreUObject\UObject\FPackageTrailerBuilder\AdditionalDataCallback) && Callback )